The number of men killed by police at a mine in South Africa on Thursday is now reported to be "more than 30," The Associated Press says. As the wire service adds, the shootings "are one of the worst in South Africa since the end of the apartheid era, and came as a rift deepens between the country's governing African National Congress and an impoverished electorate confronting massive unemployment and growing poverty and inequality."

Our original post continues:

In one of the deadliest incidents of violence in South Africa since the end of the apartheid era, police opened fire Thursday on striking miners, killing at least seven people.

The South African Press Association news agency said the shooting followed an attempt by police to disperse striking workers at Marikana, the world's third-largest platinum mine, about 40 miles northwest of Johannesburg.

Here's more from The Associated Press about the events that led to the shootings:

"The shooting happened Thursday afternoon after police failed to get the striking miners to hand over machetes, clubs and other weapons.

Some miners did leave, though others carrying weapons began war chants and soon started marching toward the township near the mine, said Molaole Montsho, a journalist with the South African Press Association who was at the scene.

The police opened up with a water cannon first, then used stun grenades and tear gas to try and break up the crowd, Montsho said.

Suddenly, a group of miners rushed through the underbrush and tear gas at a line of police officers. Officers immediately opened fire, with miners falling to the ground. Dozens of shots were fired by police armed with automatic rifles and pistols."

A video of the shooting can be seen here, but is graphic in its content.

A police ministry spokesman told the AP miners had fired at police Thursday before the fatal shootings.

In a statement, President Jacob Zuma said he was "shocked and dismayed at this senseless violence."

Earlier Thursday, Lomin, the company that owns the mine, said the striking workers would be fired unless they returned to work Friday. After the shooting, a Lomin official would only say: "It's a police operation."

Reasons for the strike are unclear, but news reports say it stems from tensions between two rival unions: the long-established National Union of Mineworkers and the Association of Mineworkers and Construction Union, which is newer and more militant.

Here's more from the AP:

"The unrest at the Lonmin mine began Aug. 10, as some 3,000 workers walked off the job over pay in what management described as an illegal strike. Those who tried to go to work Saturday were attacked, management and the National Union of Mineworkers said. On Sunday, the rage became deadly as a crowd killed two security guards by setting their car ablaze, authorities said. By Monday, angry mobs killed two other workers and overpowered police, killing two officers, officials said. Officers opened fire that day, killing three others, police said."

Mining is one of South Africa's main economic drivers, and the unrest is likely to affect production at the mine, which produces more than 90 percent of all of Lomin's platinum.

Lomin said it would lose around 2 percent of its yearly output of the precious metal. The company's share price fell more than 6 percent Thursday on the London Stock Exchange.